The present invention relates to a pump sprayer assembly for spraying liquids or fluid. More particularly, the present invention relates to a pump sprayer where the pressure in the sprayer may be supplied or increased with a conventional domestic water supply.
Pump sprayers are typically used for dispensing fluids such as cleaning fluids, insecticides, herbicides, fertilizers and other materials. Conventional pump sprayers include a supply tank or reservoir dimensioned to hold a volume of liquid, a manual pump or piston, a pressure vessel or accumulator, a bulkhead discharge fitting, a discharge valve, and a spray wand with a discharge control valve and nozzle from which the fluid is discharged. In some conventional pump sprayers, the reservoir supply tank performs its intended function and also serves the function of the accumulator or pressure vessel. In operation, the reservoir initially contains air at atmospheric pressure and the fluid to be sprayed. The operation of the pump forces air into the reservoir, thereby increasing the pressure of the air therein. The compressed air, in turn, exerts pressure on the fluid contained in the reservoir. Operation of the discharge control valve allows the pressure within the accumulator to push the fluid out through the nozzle until the valve is closed or equilibrium is reached. Others have attempted to improve upon the conventional design of the sprayer by providing a reservoir that is equipped to receive an auxiliary air charge. These changes in the basic design are called self-pressurizing sprayers and examples are found in U.S. Pat. Nos. 4,782,982, 4,930,686, and 4,930,664. In those modified designs, the reservoirs or containers have a second, separate bulkhead fitting or nipple that may be rapidly connected and disconnected to a domestic water supply. In a typical manner, the domestic water supply is a garden hose. By attaching the garden hose to the bulkhead fill fitting, the user introduces water into the reservoir and since the reservoir is sealed, compresses the air in the reservoir to provide the sprayer with an initial charge. The initial charge of air is accomplished without operating the manual pump.
Conventional self-pressurizing sprayers have one or more deficiencies. All are confronted with the problem of potential backflow into the domestic water supply. If the pressure in the sprayer is greater than the water supply pressure, it is possible that fluid in the sprayer could be forced into the domestic water supply. This would create an unsatisfactory condition where, for example, insecticide might be pumped into the water supply of a home owner. It is conceivable that if there was a sudden decrease in the domestic water supply pressure, pressurized fluid from the sprayer could be forced through the garden hose and into the domestic water supply. Then, when the user turned on a faucet, his domestic water supply would be contaminated with insecticides or other contaminants.
Another drawback of conventional self-pressurizing sprayers is that the spray container itself is modified to have two external bulkhead fittings. One fitting connects to the conventional discharge tube. The second fitting connects to the domestic water supply. By providing a second fitting on the container, new molds must be formulated for the container. The second bulkhead fitting increases the overall expense of the sprayer by requiring a new mold for the self-pressurizing container. In addition, distribution costs for sprayers are adversely affected. A distributor has to carry the conventional, single bulkhead fitting sprayers, as well as the dual bulkhead fitting sprayers. As a result, the overall cost of sprayers, including their distribution cost, is increased.
The invention provides a self-pressurizing sprayer with a single external bulkhead fitting. The invention modifies the discharge tube to have a T-type or an in-line fitting. The T-type or in-line quick-disconnect fitting couples the discharge tube to a source of domestic water supply, such as a garden hose. Once connected, the garden hose supplies water under pressure to the sealed sprayer reservoir. The water is supplied via the discharge hose and travels through the discharge tube toward the bottom of the reservoir. In the event that solid materials are disposed in the sprayer reservoir, the water from the discharge tube agitates those materials at the bottom of the sprayer container and assists in mixing those materials while the sprayer is filling.